Several reports, including the leaked Gupta emails, have suggest that Ngubane had facilitated the Gupta family’s capture of Eskom.
Allegations Ngubane will have to clarify include an accusation by former Mineral Resources Minister, Ngoako Ramatlhodi, that he and former Eskom CEO Brian Molefe tried to pressure him into blackmailing mining giant Glencore into selling its Optimum Mine to Gupta-owned Tegeta Resources.
It is also alleged that Gupta associates had drafted the first speech Ngubane made when he was acting Chairperson, in which he announced the departure of his predecessor Zola Tsotsi.
Ngubane resigned as Eskom Board Chairperson in June last year, amid reports that his passport was forwarded to Rajesh Gupta in October 2013, along with quotes for a charter flight to travel to the Central African Republic.
Ngubane has denied travelling to the CAR at the time as he said, there was fighting in the country.